Q.1
An electromagnetic wave of frequency ν=3.0 Mhz passes from vacuum into a dielectric medium with permitivity ε=4.Then [ AIEEE 2004]
  • a)Wavelength is doubled and frequency remains unchaged
  • b) Wvaelength is doubled and frequency becopmes half
  • c)wavelength is doubled and frequency becomes half
  • d)wave length and frequency both remains unchaged
Q.2
The electrical conductive it of earth's atmosphere increases with altitude because of [ Bihar CECE 2004]
  • a) reflection of atmospheres
  • b) accelerated protons
  • c)measure of voltagae
  • d)measure of charge
Q.3
If the wavelength of light is 4000 Å then the number of waves in 1mm length will be [ JKCET 2004]
  • a) 25
  • b) 0.25
  • c)0.25×104
  • d)2.5×104
Q.4
Sodium lamps are used in foggy conditions because
  • a) yellow light is scatered less by the fog particles
  • b) yellow light is scattered more by the fog particles
  • c) yellow light is unaffected during its passage through the fog
  • d) wavelength of yellow light is the mean of visible part of the sprectrum
Q.5
The rms value of electric field of the radiation coming from sun is 720 N/C, The average radiation density in J/m3 is ..
  • a)81.35 × 10⁻¹²
  • b) 3.3 × 10⁻³
  • c)4.58 × 10⁻⁶
  • d)6.37 × 10⁻⁹
Q.6
In the region closer to the oscillating charges, the phase difference between E and B fields is ... and their magnitude quickly decreases as ... with distance r from the source
  • a) 0, r-1
  • b) π/2, r-3
  • c)π/2, r-1
  • d)0, r-3
Q.7
At room temperature, if the relative permittivity of water be 80 and the relative permeability be 0.0222, then the velocity of light in water is ... m/s
  • a)3×108
  • b) 2.5×108
  • c)2.25×108
  • d)3.5 ×108
Q.8
In hertz's experiment the .... of the electromagnetic waves is equal to the kinetic energy of the charges oscillating between the two spheres
  • a)frequency
  • b) energy
  • c)wavelength
  • d)velocity
Q.9
For a radiation of 6 GHz passing through air, the wave number ( number of waves) per 1 m length is ...(1 GhZ=109 Hz)
  • a) 3
  • b) 5
  • c) 20
  • d) 30
Q.10
The power in a two-wire transmission line travels
  • a)inside the conductors
  • b) outside the conductors
  • c)none of the above
  • d)both inside and outside the conductors
Q.11
The characteristic impedance of a lossless transmission line is given by
  • a) Zo=√LC
  • b) Zo=√ (L/C)
  • c)Zo=√(C/L)
  • d)Zo=LC
Q.12
An 'antenna' is
  • a) inductive
  • b) capacittative
  • c)resistive above its resonance frequency
  • d)none of the above
Q.13
A laser is a coherent source because it contains
  • a) many wavelengths
  • b) uncoordinated wave of a particular wavelength
  • c) coordinated wave of many wavelengths
  • d) coordinated waves of a particular wavelength
Q.14
A modulating signal of frequency 5kHz and peak voltage of 6V is used to modulate a carrier of frequency 10 MHz and peak votage of 10V. what is modulation index
  • a)1.66
  • b) 0.6
  • c)2
  • d)0.5
Q.15
In above problem (Q161) what is Low side band frequency (LSB)
  • a) 10.005 MHz
  • b) 0.05 MHz
  • c)22 MHz
  • d)9.995 Mhz
Q.16
In problem Q161 What is upper side band frequency (USB)
  • a)10.005 MHz
  • b)0.05 MHz
  • c)22 MHz
  • d)9.995 MHz
Q.17
In problem Q161 what is the amplitude of LSB and USB
  • a) 3V, 6V
  • b) 6V, 3V
  • c) 3V , 3V
  • d) 6V, 6V
Q.18
Who produced the electromagnetic waves first ?
  • a)Marconi
  • b)Maxwell
  • c)J.C. Bose
  • d)Hertz
Q.19
A plane electromagnetic wave is incident on a material surface. The wave delivers momentum P and energy E
  • a) P=0, E ≠ 0
  • b)P ≠ 0, E=0
  • c)P ≠ 0, E ≠ 0
  • d) P=0, E=0
Q.20
If Vγ Vx and Vm are the velocity of the γ rays, x rays, micro waves respectively inspace, then
  • a)Vγ < Vx < Vm
  • b) Vγ=Vx=Vm
  • c)Vγ > Vx > Vm
  • d)Vγ > Vx < Vm
Q.21
If λγ ,λx and λm are the wave lengths of the γ rays, x rays and micro waves respectivelyin space then
  • a) λγ > λx > λm
  • b) λγ < λx < λm
  • c) λγ=λx=λm
  • d) λγ >λm > λx
Q.22
According to Maxwell, a changing electric field produces
  • a)emf
  • b) Electric current
  • c)magnetic field
  • d)radiation pressure
Q.23
An electromagnetic wave going through vaccum is described by E=o E sin(kx- ω t).Which of the following is independent of the wavelength?
  • a) ω
  • b)k/ ω
  • c) k ω
  • d)k
Q.24
Which of the following have zero average value in a plane electromagnetic wave?
  • a) Electric energy
  • b) Magnetic energy
  • c) Electric field
  • d)None of these.
Q.25
If the relative permeability and dielectric constant of a given medium are equal to µr and K respectively, then the refractive index of the medium is equalto__________
  • a) √(µr) K
  • b) √(µr) Eo
  • c) √(µo) Eo
  • d) √(µr)/ K
Q.26
Astraonomers have found that electromagnetic waves of wavelength 21cm arecontinuously reaching the Earth’s surface . Calculate the frequency of this radiation.(c=3 ×108m/s)
  • a)14.28 GHz
  • b)1.428 kHz
  • c)1.428 MHz
  • d)1.428 GHz
Q.27
Electric field in an electromagnetic wave is given by E=50 sinω(t-x/c) NC-1 .Intensity of this wave is ___________ Wm-2
  • a) 50
  • b)1.1×108
  • c)3.3
  • d)5.5×10⁻¹⁹
Q.28
The amplitude of the electric field in a parallel beam of light of intensity 2.0Wm-2is _______
  • a) 38.8NC-1
  • b) 19.4NC-1
  • c)9.7NC-1
  • d)None of these.
Q.29
Speed of electromagnetic wave is the same
  • a) for all wavelengths
  • b) in all media
  • c) for all intensities
  • d) for all frequencies
Q.30
The maximum electric field in a plane electromagnetic wave is 900NC-1 . The waveis going in the x direction and the electric field is in the y direction. The maximummagnetic field in the wave is ____________T
  • d)27×1010
  • a)3×10⁻⁸
  • b) 3×10⁻⁶
  • c)27×10⁻⁶
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